1. Technical Field
The present invention relates to a mobile communication system.
2. Background Art
A mobile communication system of the LTE scheme (Release.8) defined by the 3GPP, as illustrated in FIG. 18, is configured such that when a handover process of a mobile station UE is carried out from a radio base station eNB#1 to a radio base station eNB#2, an X2 bearer is set between the radio base station eNB#1 and the radio base station eNB#2 in order for a U-plane PDU (Protocol Data Unit) to be transferred from the radio base station eNB#1 to the radio base station eNB#2 via the X2 bearer.
The radio base station eNB#1 and the radio base station eNB#2, as illustrated in FIG. 18, include network layer 1/2 (NW L1/L2) functions, an IP (Internet Protocol) layer function, a UDP (User Datagram Protocol) layer function, and a GTP (GPRS Tunneling Protocol)-U layer function, as X2 bearer functions configured to set the above-mentioned X2 bearer.